		<script type="text/javascript" charset="utf-8">
			
		
		function change_user_name()
		{
			var first_name=$("#serial_first_name").val();
			var last_name=$("#serial_last_name").val();
			var name=first_name+last_name;
			name =name.toLowerCase();
			$("#user_name").val(name);
			//$('#user_name').val($(this).val().toLowerCase());
		
		}
		
		$("#serial_first_name").change( function () { 
	     	
			change_user_name();
		
	    });
			$("#serial_last_name").change( function () { 

				change_user_name();

		    });

		</script>